Calcitonin gene related peptide relaxes cholecystokinin-induced contraction in guinea pig gallbladder strips in vitro

1992 ◽  
Vol 70 (12) ◽  
pp. 1571-1575 ◽  
Author(s):  
L. W. Kline ◽  
P. K. T. Pang

Calcitonin gene related peptide has been shown to relax vascular and intestinal smooth muscle. This study examines the effects of calcitonin gene related peptide on cholecystokinin-induced contraction of guinea pig gallbladder strips in vitro. Calcitonin gene related peptide was found to cause a dose-dependent relaxation of cholecystokinin-induced tension, which was blocked by the calcitonin gene related peptide receptor antagonist human calcitonin gene related peptide8–37. Previous studies demonstrated that calcitonin gene related peptide acted directly on guinea pig gallbladder smooth muscle to inhibit acetylcholine- or KCl-induced contraction. The present results further confirm that calcitonin gene related peptide acts directly on the smooth muscle. In addition, the use of L-NG-nitroarginine methyl ester, glibenclamide, and other agents strongly suggests that calcitonin gene related peptide also acts by way of the nonadrenergic noncholinergic nervous system, to induce the relaxation of cholecystokinin-induced contraction observed in the guinea pig gallbladder strips.Key words: calcitonin gene related peptide, gallbladder, cholecystokinin.

1991 ◽  
Vol 69 (8) ◽  
pp. 1149-1154 ◽  
Author(s):  
Loren W. Kline ◽  
Toyoji Kaneko ◽  
Christina G. Benishin ◽  
Peter K. T. Pang

Calcitonin geae-related peptide (CGRP) relaxes vascular and intestinal smooth muscle. This study localized CGRP in the guinea pig gallbladder, examined the effects of CGRP on KCl- and ACh-induced contraction, and determined CGRPs site of action in the gallbladder. The gallbladder of male Hartley guinea pigs was used in in vitro tension studies, radioimmunoassay, or immunocytochemical studies. Radioimmunoassay showed that 8.0 ± 0.5 pmol/g of immunoreactive CGRP was present. Immunocytochemistry demonstrated that immunoreactive-CGRP nerve fibers occurred around blood vessels, in gallbladder smooth muscle layers, and were associated with ganglia. No immunoreactive cell bodies were observed, even after colchicine treatment. The in vitro tension studies showed that CGRP inhibits either KCl- or acetylcholine-stimulated contraction. CGRP may in part act directly on the gallbladder smooth muscle to inhibit contraction.Key words: calcitonin gene-related peptide, gallbladder, smooth muscle.


1988 ◽  
Vol 151 (3) ◽  
pp. 1113-1121 ◽  
Author(s):  
Yukio Hirata ◽  
Yasuyuki Takagi ◽  
Shoichiro Takata ◽  
Yuka Fukuda ◽  
Hiroki Yoshimi ◽  
...  

1986 ◽  
Vol 250 (4) ◽  
pp. H693-H698 ◽  
Author(s):  
A. Saito ◽  
S. Kimura ◽  
K. Goto

The potential neurotransmitter role of calcitonin gene-related peptide (CGRP) in cardioacceleratory nonadrenergic noncholinergic (NANC) nerves was examined in the guinea pig right atrium in vitro. In the presence of atropine, a muscarinic antagonist, and atenolol, a beta-adrenoceptor antagonist, transmural nerve stimulation (TNS) of the isolated right atrium caused a positive chronotropic response, which is slow in both onset and decay. This TNS-induced slow response was assumed to be mediated by NANC nerves in the right atrium since tetrodotoxin inhibited the response. Dense distribution of CGRP-like immunoreactive (CGRP-I) nerves was demonstrated in the sinus node. Exogenously applied CGRP exerted a positive chronotropic effect on the isolated right atrium in a dose-dependent manner. Both CGRP-I nerves and NANC response induced by TNS were not affected by surgical sympathectomy and reserpine pretreatment but were abolished by the pretreatment of animals with capsaicin. The results suggest that CGRP is the neurotransmitter of cardioacceleratory NANC nerves in the right atrium of the guinea pig.


Sign in / Sign up

Export Citation Format

Share Document